• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.815-820
• /
• 1991

4축 자유곡면가공에 있어서 공구간섭 문제는 가공형상의 취득성 뿐만 아니라 가공의 정밀도를 위하여 매우 중요한 고려사항이다. 공구의 접근자세가 고정된 3축 밀링가공의 공구 간섭에 관한 기존의 많은 연구가 있지만 이러한 연구는 공구의 접근자세가 변하는 4축 밀링가공에의 적용이 곤란하다. 왜냐하면 곡면의 형상에 따라 공구몸체의 곡면사이의 간섭문제가 부각되며, 이에 따른 공구자세의 창출문제가 해결되어야 하기 때문이다. 따라서 본 논문에서는 4축가공에서 발생할 수 있는 공구 간섭을 유형별로 분류, 각 간섭들을 발견하고 해결할 수 있는 방법의 전개와 이 방법을 이용하여 공구경로를 산출하고 그래픽 시뮬레이션과 실제의 시험절삭을 통하여 제시된 방법의 유효성을 검증한다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.683-689
• /
• 1996

5축 가공기는 가공중의 공구자세 변화를 요구하는 복잡한 산업형상의 가공, 혹은 경사 가공을 통한 표면조도 향상등의 목적으로 채용되는 첨예의 공작기계로서 이를 지원하는 CAM연구가 활발히 이루어지고 있다. 그러나, 산업현장에서 흔히 5축 가공기로 일컬어지는 상당수의 5축 가공기는 기구축은 5축을 가지나, 동기제어 축수는 3측인 “선택적 3/5축 가공기”의 형태로서 진정한 의미의 5축가공기와는 근본적으로 다르다. 5축 동기제어를 지원하는 CAM연구는 부분적으로 연구 개발된 상태이나, 선택적 3/5축을 지원하는 CAM 이론은 연구된 바 없으며, 이에 따라 현장에서는 공작물의 셋업을 변경시키는 소위 자동 인덱싱 방식으로 활용하고 있는 실정이다. 본 연구팀에서는 선택적 3/5축 가공기에서 5축 가공을 실현할 수 있는 공구경로 산출 및 제어알고리즘을 개발하고 있으며, 본 논문에서는 (5축 가공 대비) 선택적 3/5축 가공문제의 이론적 특성과 경사가공을 수행하기 위한 알고리즘을 소개하고 시뮬레이션을 통하여 유효성을 보인다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.05a
• /
• pp.189-189
• /
• 2004

본 논문은 CNC 밀링머신을 이용한 절삭가공 등 2축시스템의 위치제어 시스템을 대상으로 한다. 기존의 제어방식은 크게 독립축제어와 상호결합제어로 분류할 수 있다. 독립축제어는 두 축의 통합된 운동을 각각의 독립된 축에 대한 추적제어를 수행하여 원하는 공구경로의 위치 정밀성을 향상시키고자 하는 것이고, 상호결합제어는 지령경로에 대한 추적성능보다는 현재의 윤곽오차를 감소시키는 방향으로 제어입력을 인가하여 가공윤곽의 오차를 감소시키는데 주목적이 있다. 또한 최근의 작업공정의 고속화 경향은 윤곽오차를 감소시키면서도 추적성능이 우수한 제어방식을 요구하고 있다.(중략)

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.11
• /
• pp.3066-3073
• /
• 2009

Joint paths of master and branch pipes are induced mathematically for many kinds of joint patterns between both pipes in 3-axis pipe profile-cutting machines. By compensating them with a kerf width, the real cutting paths are determined, and their CL-data are generated, and the tool paths generated by CL-data are verified by a ghost function. A bevelling of welds is implemented through tilting a cutting torch in the $\beta$-axis direction for 8 sections in the chuck rotation of $\alpha$-axis. A PLC controls simultaneously position and velocity in a real time for $\alpha$, X, $\beta$-axis by loading CL-data generated. We developed the PLC-controlled 3-axis pipe profile-cutting system which can cut a master or branch pipe along the cutting path and simultaneously do a bevelling process.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.8
• /
• pp.48-53
• /
• 2010

5-axis CNC machining now is getting popular because it can deal with complex shapes such as impeller, turbine blade and propeller without additional equipment or process, proving a set of various tool orientations. CAM software related to 5-axis machining is being developed quickly so that users can take advantage of potential capacities of 5-axis machine tools. However, only a few researches can be found in the area of control strategy development for 5-axis machining. This paper proposes a 5-axis cross-coupling control system based on a novel tool orientation error model. The proposed tool orientation error model provides accurate information on the tool orientation error in real time, which in turn enables directly controlling the tool orientation accuracy. The proposed control system also employs a contour error model to calculate the contour error and reflect it in the control as well. The accuracy of the proposed tool orientation error model is verified and the performance of the 5-axis cross-coupling control system in terms of both contouring and tool orientation accuracy is evaluated through computer simulations compared with existing 5-axis control systems.

• Journal of the Korean Society for Precision Engineering
• /
• v.32 no.11
• /
• pp.983-988
• /
• 2015

This paper details a new ultra-precise turning method for increasing surface quality, "Multi Point B Axis Control Method." Machined surface error is minimized by the compensation machining process, but the process leaves residual chip marks and surface roughness. This phenomenon is unavoidable in the diamond turning process using existing machining methods. However, Multi Point B axis control uses a small angle (< $1^{\circ}$) for the unused diamond edge for generation of ultra-fine surfaces; no machining chipping occurs. It is achieved by compensated surface profiling via alignment of the tool radial center on the center of the B axis rotation table. Experimental results show that a diamond turned surface using the Multi Point B axis control method achieved P-V $0.1{\mu}m$ and Ra 1.1nm and these ultra-fine surface qualities are reproducible.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.9 no.3
• /
• pp.169-177
• /
• 2000

In machining screws which are important members in mono pumps or progressive cavity pumps CNC turning center with 3 axes is usually used. This sort of screw machining requires large amount of CL data points and rotational tools are used in machining. When working out the CL data points consideration of possible tool interference is important in order to avoid undercut. This paper describes the checking methods of tool interference in the screw machining on the CNC turning center. First of all a specific shape of a screw cross-section that could commonly be applied to all screws was chosen and then possible tool interference associated with that shape was identified. Checking method was mathematically developed and verified. This checking method will be utilized in the CAM system developed by the authors for screw machining on the 3-axis CNC turning center.

• Journal of Practical Engineering Education
• /
• v.13 no.2
• /
• pp.327-332
• /
• 2021

Materials used for education include SM20C, Al6061, and acrylic. SM20C materials are used a lot in certification tests and functional competitions as carbon steel, but they are also used in industrial sites. Al6061 is said to be a material that produces a lot of tools because it has lower hardness than carbon steel and is highly flexible. When practical guidance is given to students using acrylic materials, it is a material that causes vibration and tool damage due to excessive cutting. In this process, we examine how impact on the 5-axis equipment 2NC head can affect precision control. The weakest part of a five-axis equipment is the head that controls the AC axis. In the event of precision and cumulative tolerances in this area, the precision of all products is reduced. Thus, a key part of the 2NC head, the spindle housing was carried out using Al7075 T6 (U.S. Alcoasa) material and the entire body using FCD450 (spherical graphite cast iron). In the vibration and cutting process acting on these two materials, the analysis was carried out to determine the value of applying the force as a finite element analysis under extreme conditions. We hope that using these analytical data will help students see and understand the structure of 5-axis machining rather than 5-axis cutting.

• Journal of Practical Engineering Education
• /
• v.14 no.1
• /
• pp.119-125
• /
• 2022

Materials used for education are materials such as SM20C, Al6061, and acrylic. SM20C materials are carbon steel and are often used in certification tests and functional competitions, but are also widely used in industrial sites. The Al6061 material is said to be a material that has lower hardness and stronger flexibility than carbon steel, so it is a material that generates a lot of compositional selection of tools. If students are taught practical training using acrylic materials, vibration occurs due to excessive cutting in some parts and damage to the tool occurs. In this process, we examine to what extent the impact on the 2NC head, which is a five-axis equipment, can affect precision control. The weakest part of the five-axis equipment can be said to be the weakest part of the head that controls the AC axis. When the accuracy and cumulative tolerance of this part occur, the accuracy of all products decreases. Therefore, the core part of the 2NC head, the spindle housing, was carried out using an Al7075 T6 (Alcoa, USA) material. In the process of vibration and cutting applied to this material, the analysis was conducted to find out the value applied to the finite element analysis under extreme conditions. It is hoped that this analysis data will help students see and understand the structure of 5-axis machining rather than 5-axis cutting.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.6
• /
• pp.83-88
• /
• 2000

In machining large screws such as those of extruders, it takes long time to machine them on conventional machines which usually use single-tipped fixed tools. And it is also difficult to use an existing CAD/CAM coftware when trying to get over the problems of conventional machines and making use of CNC machines. In this paper, generation of machining program using rotational tools for large screws defined by longitudinal-section profile is descrebed. Use of rotational tools in machining plays an important role in saving machining time. In the sort of extruder screws, it is easy to define a screw shape by longitudinal-section profile, and by which improvement of dimensional accuracy can be expected. The CAM software developed in this paper is based on user's and designer's friendliness.